Hot air aggregate

ABSTRACT

The invention relates to an arrangement in a hot air aggregate comprising a cover ( 2 ) having a built-in fan ( 3 ), an enclosed chamber ( 4 ) after said fan ( 3 ) which extends into a conically formed, front portion ( 5 ), to which a burner unit ( 7 ) having an enclosed burner ( 9 ) supplied with a gas flow and a nozzle ( 10 ) are provided via a connecting coupling sleeve ( 6 ). Said fan ( 3 ) is fixed via a sealing means ( 11 ) against an inner tube ( 12 ) insulated from said cover ( 2 ) and delimits the back portion ( 13 ) of the enclosed chamber ( 4 ) and its opposite front portion ( 14 ) extends into the conical portion ( 5 ), which comprises on its inner mantle surface ( 15 ) inclined wings to give the streaming air through the same an extra rotation before its passage into the burner ( 9 ), said chamber ( 4 ) comprises an air guard ( 16 ) for sensing the right air flow into the burner ( 9 ) at the same time as in front of or after said fan ( 3 ) there are within said cover ( 2 ) integrated an electronic controlling unit ( 17 ) and a magnetic valve ( 18 ) for adjusting of air- and gas flows, said burner unit ( 7 ) comprises an adjusting means ( 19 ) for ignition and starting of the fan ( 3 ) when the pressure has been increased sufficiently in the chamber ( 4 ) at the same time as a sensor gives a signal to said magnet valve ( 18 ) to open said gas supply for ignition of a gas flame enclosed in the burner, and said nozzle ( 10 ) is double mantled having the possibility of cooling by aid of cooling air in the gap space ( 20 ) of the double mantle ( 21 ).

The present invention refers to an improvement in a hot air aggregatecomprising a cover having a fan built into the same, a closed chamberafter the fan which extends into a conically formed, front portion, towhich a burner is connected through a connecting sleeve, said burner issupplied with a gas flow and a nozzle. The hot air aggregate accordingto the invention is primarily intended to be used in a welding machinefor applying a roof covering material.

Presently, different types of devices are used during the application ofroof covering material and one example of such a device is a movablewagon having wheels and rollers, which is intended to join together twounrolled rolls of roof covering in connection to a joint. This is madein such a way that respective roof covering material in the joint areais heated by hot gas, which by aid of a nozzle is blown into the jointat the same time as the wagon is moved forward and by aid of itspressing roller presses together the covering layers lying on top ofeach other, said layers constitute the joint when the wagon is movedforwards, so that the melted material from the roof covering forms anadhesive. Usually these welding machines comprise a LPG-tube from whicha gas is supplied through a strong supplying pipe up to a hot air burnersituated in the end of the gas pipe, where there is a nozzle, throughwhich the hot gas can be fed out. By placing the hot gas burnerimmediately before said nozzle a totally closed combustion occurs, sothat only a mixture of nitrogen and carbon dioxide remains in the hotgas flowing out from said nozzle. This means that in the present case itis not the question about a totally open flame as in the normal case,i.e. from direct flowing of gas from for example a LPG-source which canresult in that the warming up area starts to burn. One problem with thistype of hot gas burner is that it is difficult to handle owing to itsheavy, ungainly design, and complicated control functions for adjustingof the air- and gas flow. Further there is a large risk of burning atthe nozzle in this design, which in use has a very high temperature.

The object of the present invention is to provide a new type of hot airaggregate which eliminates the problem mentioned above, and which has adesign which is easy and simple to handle having integrated adjustingfunctions for air- and gas flow. The characterizing features of theinvention are stated in the claims enclosed.

Thanks to the invention a hot air aggregate has been provided which inan excellent way fulfils its purposes at the same time as it also ischeap and easy to manufacture. The flexibility of the aggregate isattained by means of primarily the supplying pipes for gas andelectricity to the motor and possible any hand burners and also sensorsof different kind for adjusting of air- and gas flows are integrated inthe design itself. The burner unit itself comprises according to theinvention a press button for ignition and start of the fan, when thepressure has been increased enough, so that a pressure guard gives asignal to a magnetic valve, which opens the supply of gas, so that theaggregate is ignited. In the closed chamber, which is located after thefan, also an air guard is provided, which during insufficient gas flowautomatically shuts off said burner. Furthermore, the nozzle has beenprovided with a double mantle for eliminating risks of burning.

The invention is described in more detail below by means of a preferredembodiment example during reference to the drawings enclosed, in which,

FIG. 1 shows a schematic side view of a hot air aggregate according tothe invention, partly in exploded view,

FIG. 2 shows a side view of the hot air aggregate illustrated in FIG. 1in a mounted state,

FIG. 3 is a schematic cross section through the burner, showing theouter cover having an inner tube provided in the same and insulatedtherefrom for constituting a place for the fan and also a closed chamberafter the same,

FIG. 4 is a schematic, partial, perspective view partly in section ofthe hot air aggregate illustrated in FIGS. 1 and 2, and

FIG. 5 shows an example of a gable for the actual hot air aggregate.

As can be seen in more detail from the drawings a preferred example of ahot air aggregate 1 according to the invention is illustrated, whichcomprises a cover 2 having a built-in fan 3, a closed chamber 4 afterthe fan 3, which extends into a conically formed, front portion 5. Inthe front portion 5 a burner unit 7 and a nozzle 10 are provided in aconnecting sleeve 6. An enclosed burner 9 is provided in the burner unit7, said burner is supplied with a gas flow from a gas pipe 8.

In the embodiment illustrated the fan 3 is fixed via sealing means 11against an inner tube 12 which is insulated from said cover 2 and at thesame time delimits the back portion 13 of the closed chamber 4 while itsopposite front portion 14 extends into the conical portion 5. Theconical portion 5 is provided with wings on its inner mantle surface 15,not illustrated on the drawing, in order to give the flow air throughthe same an extra rotation before its passage into the burner 9. Thechamber 4 has an air guard 16 in the form of a bent pipe 17 in order todetermining the right flow of air to the burner 9 at the same time asupstreams or downstreams said fan 3 there are integrated inside saidcover 2 an electronic adjusting unit 17 and a magnetic valve 18 foradjusting of air- and gas flows. The burner unit 7 comprises anadjusting means 19 by aid of which the starting of the fan 3 can takeplace and an ignition of a gas flame within said burner 9, if thepressure is increased enough in said chamber 4 at the same time as asensor, not closer illustrated on the drawing, gives a signal to saidmagnetic wall 18 to open the gas supply for ignition of the gas flame inthe burner. In the example illustrated the nozzle 10 is double mantledhaving a possibility of cooling by aid of cooling air in the gap space20, which said double mantle 21 comprises.

The gap space 20 in said double mantling 21 of said nozzle 10 comprisesan insulating material 22 preferably in the form of a ceramic layer onthe inside 23 of the outer mantle 24. The back portion 25 of the hot airaggregate 1 comprises air intakes 26 in its back gable wall 27 and/or inthe back area 28 of the sides 29 of the cover 2.

In the present case the nozzle 10 can be provided with a branch offmeans 30 for connecting of a traditional, electrically driven hot airgun for increasing of the effect of the outstreaming hot air.

1. An arrangement for a hot air aggregate comprising a cover (2) havinga built-in fan (3), a closed chamber (4) after said fan (3) whichextends into a conically formed front portion (5) to which a burner unit(7) with an enclosed burner (9) supplied with a gas flow and a nozzle(10) are provided via a connection sleeve (6), characterized in thatsaid fan (3) is fixed via sealing means (11) against an inner tube (12)insulated from said cover (2) and delimits in the longitudinal directionof the hot air aggregate (1) the back portion (13) of the enclosedchamber (4) and its opposite front portion (14) extends into the conicalportion (5), showing on its inner mantle surface (15) inclined wings forgiving the air supplied through the same an extra rotation before itspassage into the burner (9), said chamber (4) comprises an air guard(16) for sensing the right air flow up to the burner (9) at the sametime as in front of or after said fan (3) there are integrated withinsaid cover (2) an electronic controlling unit (17) and a magnetic valve(18) for adjusting of air- and gas flows, said burner unit (7) comprisesadjusting means (19) for ignition and starting of said fan (3) when thepressure has been increased sufficiently in the chamber (4) at the sametime as a sensor gives a signal to the magnetic valve (18) to open thegas supply for ignition of a gas flame enclosed in the burner, and saidnozzle (10), is double mantled having the possibility of cooling by aidof cooling air in the gap space (20) of the double mantle (21).
 2. Anarrangement according to claim 1, characterized in that the gap space(20) in the double mantle (21) of the nozzle (10) is provided with aninsulating material (22) preferably in the form of a ceramic layer onthe inside (23) of the outer mantling (24).
 3. An arrangement accordingto claim 1, characterized in that the back portion (25) of the hot airaggregate (1) is provided with air intakes (26) in its back gable wall(27) and/or in the back area (28) of the sides (29) of the cover (2). 4.An arrangement according to claim 1, characterized in that said nozzle(10) comprises a branch off means (30) for connection to a traditionalelectrically driven hot gun for increasing the effect of the outcominghot air.